I’ve just discovered your site, You should probably be aware that there is a syndication standard called ‘ESF’, the Epistula Syndication Format, invented at the height of the ‘RSS needs to be extended’ argument two years ago. It’s more or less obscure, but a high number of people are still generating it (Sam Ruby, for example, at http://www.intertwingly.net/feeds/) and there exists a number of modules and extensions for weblogging systems to use it. The spec is at http://www.aquarionics.com/article/name/esf.
I would – as the creator of an existing syndication standard – prefer it if your syndication standard extension did not share the name, to be honest.